<!DOCTYPE html>
<html>
<head>
	<title></title>
	<style type="text/css">
		canvas{
			border: 1px solid #333;
		}
	</style>
</head>
<body>
	<canvas width="600" height="400" id="canvas"></canvas>
	<script type="text/javascript">
		//相当于拿到一张纸
		var canvas=document.getElementById("canvas");
		//获取画笔
		var ctx=canvas.getContext("2d");

		ctx.translate(300,200)

		//绘制圆
		ctx.arc(0,0,150,0,270*Math.PI/180,false)
		ctx.lineTo(0,0)
		ctx.lineTo(150,0)
		ctx.lineWidth=5;

		ctx.fillStyle="tomato";
		ctx.fill()
		ctx.stroke()

	</script>
</body>
</html>
